Every laser is unique and individual. No way to know what you're gunna get. The peak power from an X-65 could be between 65 and 499mW. If you want the guarantee of extra power, yes, you'll want to pay the extra cost of an X 85.
Well that would be the peak also meaning it wouldn't be over a good amount of time. Really in my opinion if you're going for higher powered lasers you might as well get the best you can afford. There is no doubt that the X-85 will be better. You might as well go for the X-105 though.